B88 exchange functional

To calculate free energies of solvation for several organic molecules, Fortunelli and Tomasi applied the boundary element method for the reaction field in DFT/SCRF framework173. The authors demonstrated that the DFT/SCRF results obtained with the B88 exchange functional and with either the P86 or the LYP correlation functional are significantly closer to the experimental ones than the ones steming from the HF/SCRF calculations. The authors used the same cavity parameters for the HF/SCRF and DFT/SCRF calculations, which makes it possible to attribute the apparent superiority of the DFT/SCRF results to the density functional component of the model. The boundary element method appeared to be very efficient computationally. The DFT/SCRF calculations required only a few percent more CPU time than the corresponding gas-phase SCF calculations. 

B88 exchange functional with Lee, Young and Parr s correlation functional complete active space SCF... 

The p parameter is determined by fitting to known data for the rare gas atoms using the dimensionless gradient variable x. The B88 exchange functional has the correct... 

The B88 exchange functional (Becke 1988) is the most popular GGA exchange functional in quantum chemistry calculations at present. This functional was derived for the form in the low density/high density gradient region to satisfy the, far-from-nucleus (long-range) asymptotic interaction condition (see Chap. 8) such as... 

The PW91 exchange functional (Perdew 1991 Perdew and Wang 1992) is a reformulation of the B88 exchange functional designed to satisfy as many fundamental physical conditions as possible ... 

As described thus far, the mainstream GGA exchange functionals are the B88 exchange functional and its modifications for satisfying fundamental physical conditions at present. Now let us examine an exchange functional that was developed from a different standpoint, the parameter-free (PF) exchange functional (Tsuneda and Hirao 2000). This functional is directly derived from a density matrix expansion at the Fermi momentum (Negele and Vautherin 1972),... 

The B3LYP hybrid functional (Becke 1993), the first hybrid functional, is the most frequently used functional (or method) in all functionals (or all theories) in quantum chemistry calculations. This functional uses three parameters as the mixing ratios to form the adiabatic connections between the Hartree-Fock exchange integral and the LDA exchange functional and between the LYP-GGA correlation functional and the LDA correlation functional, and to combine with the attenuated GGA term of the B88 exchange functional. 

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